1. Field of the Invention
The present invention relates generally to the field of shell feeding and loading apparatus for guns, particularly, of automated shell feeding and loading apparatus for cannon.
2. Discussion of the Prior Art
Armored vehicles, in particular military tanks and mobile guns platforms, are widely considered, even in the nuclear age, to be the backbone of land-based military forces. As a result, there is a continual escalation in the development of improved and more survivable tanks and gun platforms on the one hand and in the development of improved and more potent anti-armor weapons on the other hand. In general, because of continual improvement in anti-armor weapons, modern tanks are constructed with more, and usually heavier, armor, which in turn usually results in the tanks being larger and more massive. This, in turn, generally requires larger and more powerful engines, transmissions and so forth, which require the tank to be still larger and more massive. In addition, because of tanks being more heavily armored, the tanks are required to mount larger, and more powerful cannon to combat heavily armed enemy tanks.
As tanks become heavier and larger they tend to become more mechanically complicated and very greatly more costly to purchase, operate and maintain. Moreover, weight and size limits are reached which make the tanks difficult or impossible to air transport, and existing roads, bridges and other structures may not be sufficiently strong to support the tank's weight.
Still further, the increased size of heavily armored tanks of current design results in a relatively large target profile which tends, in and of itself, to result in increased tank vulnerability to anti-armor weapons, thereby necessitating still more armor and still larger size. An additional consideration is that large tanks require relatively large tank crews and thus military manpower limitations alone may limit the number of large tanks that can be fielded.
As a result of such factors, it is considered by many that present main battle tanks are about as large and massive as is practical and may, nevertheless, be vulnerable to enemy anti-armor weapons. Thus, there is a current emphasis in many countries of the world to produce smaller tanks which, while still being heavily armored to protect the crew, have smaller target profiles and which preferably have reduced crew requirements.
A factor which has contributed to the large size and comparatively high profile of modern tanks is that the tank's cannon have typically been mounted within large, heavily armored turrets which also at least partially house a typicaly three man gun crew of gun commander, gun opreator and gun loader. Height is ordinarily provided in the tank for the gun loader to stand upright to enable loading shells from a shell magazine into the gun.
In order to reduce tank size and profile height, numerous new tank designs eliminate the conventional massive gun turret and, instead, mount the cannon exteriorally on top of a relatively small armored vehicle. Since, in such designs, the cannon is outside the crew compartment, automated loading of the cannon is needed for transferring shells from the vehicle upwardly into the cannon for firing. An important advantage associated with the provison of autoloading apparatus is that the previously-required gun loader is no longer required, thus reducing crew size. Furthermore, overall height of the tank can be reduced, in some instances by a significant amount, since head clearance for a standing shell loader crewman is no longer required and all crewmen in the tank can operate the vehicle and gun from a selected position.
The required autoloading apparatus for such externally mounted cannon are generally required to operate in a relatively restricted space and are typically required to move shells along a relatively complicated path from a magazine extraction position within the vehicle into the breech of the cannon. In addition, it is generally required that the autoloading apparatus operated in a reliable manner enabling comparatively rapid firing of the cannon. Furthermore, it is oridinarily required that the autoloading system have capability for selectively feeding more than one type of shell to the cannon according to the type of target under firing attack.
Such autoloader requirements are especially difficult to meet when, as is ordinarily the situation, the exteriorally mounted cannon with which the autoloading system is to be used is of a preexisting type configured for manual loading. The autoloader must then, in a very much more limited space, duplicate many of the shell loading motions of a human crewman, while at the same time usually having poor access to the cannon because of the manner in which the cannon is mounted outside the vehicle.
For these and other reasons, improvements in shell autoloading systems, particularly for exteriorally mounted cannon on tanks and the like, are needed to meet the requirements of next generation, low profile armored vehicles.